Bis (tetraalkyldiamidophosphoryl) alkanephosphonates



pho'sphoryl) a1 Patented Oct. 6, 1953 umrso OFFICE 2,654,781 131swermmmnmm omosrnonm YALK-ANEPHOSPHONATES Henry Tolkniith; Midland, Mich., asslgnor m The Dow Chemical -Gompany, Midland, :Micln, -9. ="corp'oratio'n of Delaware Nd-Dravtin'g, Appueauonhugm 1 7,11 951, Serial No. 2425402 ":01am. (outta-545) a novehmethod for the production offpol'yphosphate compoun'ds The newcompoundsarebis'(tetraalkyldiamidokanephosphonates 'of the -formula In this and succeeding" formulae, each -R represents an alkyl radicabcontainingirom 1 to 4 carbon atoms, inclusive, and (-R' represents an alkyl radical containing -1 or 2- carbon atoms.

These triphosphates are viscous oils, somewhat soluble in many organic solvents and water.

They are of particular valueas toxic constituents of parasiticidecompositionsand as intermediates -for :the preparation of -=other phosphate derivatives.

The new compounds may :be: preparedibyinixwing or'iother-wise blending a compound of the iormu-la is up sis x R\N/ withacompound-ofmerermum wherein "X a member of the *group consisting of chlorine and ('RQ and Y is "the other member of said group. The mixture is then heated at a temperature of from*'90? to 135 C.

whereby alkyl chloride is evolve'd (RC1) the "heating being continued until the evolution of alkyl chloride of reaction is substa'ntially com- "mete.

Although the theory governing the reaction is rine in the *tetraalkyldiamidophosphoricchloride or the methaneph'osphonic dichloridemay beere- "covered as alkyl chloride. The pr dces's m-ight -be represented as 'tak'in'g place according to either or both ot the following equations "iljheipropoitionof at Ieast 2 moles of theoalkyI tetraalkyldiamidophosphate per mole of alkaiiephosphonic "dichloride ('as shown in Equa- "tion A) "amine proportion was least 2mo1es of tetraalkyldiamidophosphoric chloride per mole 4-0 of 0,0-dialky1 alkanephosphonate (as shown in Equation *3) is critical for the accomplishment of the desired reaction, i.-e. the synthesis of the bis(tetraaikyldiamidophosphoryl) alkanephos- :phonates. Ji -desired, a small excess of the 0- '45 alkyl 'tetraalkyldiamidophesphate or the tetraalkyldiamidophosphoric chloride maybe em- '-ployed, and -a largevexcess-does not affect the vcourse--of the reaction butis undesirable from the'standpoint of economy. A'significantly lesser proportion-ismotdesirable since it reduces the yield ofithe desired compound and results in i the "formation of other phosphate derivatives.

Thereaction Of-thepresent invention proceeds *sznoothly at the-temperature range of from 55 to C. Since the' desiredrproducts are somecarried out over a period of from one to six hours or longer, extended periods-being employed the lower temperatures. In operating at a temperature of from 125-135 C., the reaction is essentially complete in about 2 hours.

In carrying out the process of the present invention, the total reactant charge may be mcchanically mixed and then heated for a period of time.

Alternatively, either reactant maybe added portionwise to the other under conditions of elevated temperature in the reaction vessel. In another procedure the reaction mixture may be heated at atemperature or 90 C. or somewhat higher for a time, and the temperature thereafter raised to from 125 to 135 C. fora short period to complete the reaction. If desired,

the reaction may be carried out in an inert organic solvent such as toluene, xylene, and

chlorobenzene. v

The contacting'o'f'the reactants as above described may be carried out under any practical operating pressure. produced in the process are frequently gases or low boiling liquids, operation under somewhat increased pressure is sometimes preferred in order to avoid the loss of the alkyl chloride byproducts. However, where it may be desired to recover the by-products as produced, the operation may be carried out at atmospheric or reduced pressure; and such separation and recovery of alkyl chloride as formed, constitutes a preferred embodiment of the invention.

A potentially valuable mode of operation consists of carrying out the foregoing preparation as a continuous process. Thus, the reactants may be mixed orbtherwis blended'and' metered through a suitable reaction zone of controlled temperature, at such a rate as to accomplish the formation of the desired, compound in high yield during the reaction interval. In such operation, an suitable pressureand temperature may be maintained, and icy-product alkyl chloride bled out of the system as desired.

Following the reaction, the mixture may be distilled under reduced pressure and under 135 C. to separate low boiling constituents and to obtain as a residue the desired bis(tetraall yldiamidophosphoryl) alxanephosphonate product.

The following examples illustrate the invention but are not to be construed as limiting the same:

- Example 1 30.6 grams (0.17 mole) of O-ethyl tetramethyldiamidophosphate (having a density of 1.0230 and a refractive index n/D 1.4409 at C.) and 11.3 grams (0.085 mole) of methanephosphoric dichloride were mixed together and the resulting dispersion heated with agitation at a temperature of from 95 to 100 C. until no further substantial amounts of ethyl chloride of reaction were liberated. During the heating, ethyl chloride was separated and recovered from the reaction zone as formed. A bis(tetramethyldiamidophosphoryl) methanephosphate product was thereby obtained in substantially quantitative yield as a yellow viscous oil having a refractive index n/D of 1.4685 at 20 C.

Since the allzyl chlorides -propyldiamidophosphoryl) Example 2 10.2 grams (0.04 mole) of N,N-dimethyl-N,N'- dibutyldiamidophosphoric chloride (having a density of 1.0420 and a refractive index n/D of 1.4658 at 20 C.) and 2.5 grams (0.02 mole) of 0,0-dimethyl methanephosphonate (having a density of 1.1639 and a refractive index n/D of 1.4118 at 20 C.) were mixed together and the resulting dispersion heated at a temperature of C. until the evolution of methyl chloride of reaction was substantially complete. The heating was carried out with stirring and over a period of about 2.5 hours. During the heating, methyl chloride was separated and recovered from the reaction zone as formed. A bis(N,N-dimethyl-N ,N -dibutyldiamidophosphoryl) methanephosphonate product was thereby obtained in substantially quantitative yield as a viscous oil 6 having a refractive index n/D of 1.4622 at 20 C.

Example 3 10 grams (0.0296 mole) of tetrabutyldiamidophosphoric chloride (having a density of 1,025? and a refractive index n/D of 1.4661 at 20 C.) and2.04 grams (0.0148 mole) of 0,0-dimethyl ethanephosphonate (having a density of 1.0418

and a refractive index n/D of 1.4154 at 20 C.) were mixed together and the resulting dispersion heated at a temperature of 120 to C. until no further substantial amounts of methyl chloride of reaction were liberated. The heating was carried out with stirring and over a period of about 2 hours. During the heating, gaseous methyl chloride was separated and recovered from the reaction'zone as formed. A bis(tetrabutyldiamidophosphoryl) ethanephosphonate product was thereby obtained in substantially quantitative yield as a viscous oil having a refractive index n/D of 1.4620 at 20 C. and a molecular weight of 718 as compared to a theoretical molecular weight of 714.

In a similar manner, other bis(tetraalkyldiamidophosphoryl) alkanephosphonates may be prepared as follows:

Bis-N-methyl-N-isopropyl- -N- methyl-N-isomethane phosphonate by reacting together O-methyl-N-methyl- N-isopropyl -N'- methyl NT isopropyldiamidophosphate and methanephosphonic dichloride.

Bis(tetraethyldiamidophosphoryl) ethanephosphonate by reacting together O-butyl tetraethyldiamidophosphate. and ethanephosphonic dichloride.

Bis(N,N dimethyl-N,N-diisopropyldiamidophosphoryl) ethanephosphonate by reacting together N,N-dimethyl-N,N-diisopropyldiamidophosphoric chloride and 0,0-dibutyl ethanephosphonate.

Bis (N,N-dimethyl -N;N- diethyldiamidophosphoryl) methanephosphonate by reacting together N,N-dimethyl-N ,N diethyldiamidophosphoric chloride and 0,0-diethyl methanephosphate.

' Bis(N,N diethyl N,N' dibutyldiamidophosphoryl) ethanephosphonate by reacting together O-propyl N,N-diethy1-N ,N -dibutyldiamidophosphate and ethanephosphonic dichloride.

The O-alkyl tetraalkyldiamidophosphates employed as starting materials, as above described, may be prepared by reacting a tetraalkyldiamidophosphoric chloride with a suitable sodium alcoholate. Satisfactory yields are obtained when employing one molecular proportion of the tetraalkyldiamidophosphoric chloride for each proportion of the alcoholate. The reaction takes place successively to displace two of the chlorines in the phosphorus oxychlorides with amido groups. In this formula R and R represent the same or different alkyl radicals containing from 1 to 4 carbon atoms, inclusive. The reaction is carried out in a suflicient excess of the amine reactant to act as acceptor for by-product hydrogen chloride.

Where it is desired to introduce two identical amido groups into the molecule, 1 molecular proportion of the phosphorus oxychloride is reacted with 2 molecular proportions of the amine. Where it is desired that the substituting amido groups differ, 1 molecular proportion of the phosphorus oxychloride is successively reacted with one molecular proportion of each amine.

The reaction takes place smoothly at the temperature range of from to 40 C. The reaction is somewhat exothermic and the temperature may be controlled by the addition and subtraction of heat, if required. Upon completion of the reaction, the crude mixture may be filtered and the filtrate fractionally distilled under reduced pressure to separate the desired product.

The alkanephosphoric dichlorides employed as starting materials in the present process may be prepared as reported in Beilstein, second edition, first supplement, volume 4, page 595. These materials have the following boiling points:

Compound Boiling Point CH3POC12 163 0. at 760 millimeters pressure. CQH5POO12 175 C. at 760 millimeters pressure.

C. The reaction is somewhat exothermic,

wherein each R represents an alkyl radical containing from 1 to 4 carbon atoms, inclusive, and R represents a member of the group consisting of methyl and ethyl. 2. Bis(tetramethyldiamidophosphoryl) methanephosphonate having the formula CHaCHzCHzCHa ethane- O OHaCHzCHiOHI O CHaCHzCHzCHz/ N CHaCHzCHzCHz 2 4. Bis(N,N dimethyl N',N' dibutyldiamidophosphoryl) methanephosphonate having the formula P-CHaCBZI 0 0 CH3 CHaCHaCHaCHz/ N/ CHaCHzCHzC'Hz 2 with one molecular of the formula proportion of a compound 0 Y R i in which formulae each R is an alkyl radical containing from 1 to 4 carbon atoms, inclusive, R is an alkyl radical containing from 1 to 2 carbon atoms, inclusive, X is a member of the group consisting of chlorine and RO- and Y is the other member of said group and (2) heating said mixture at a temperature of from to C. until the evolution of alkyl chloride of reaction is substantially complete.

HENRY TOLKMITH.

No references cited. 

1. A BIS(TETRAALKYLDIMIDOSPHOSPHORYL) ALKANEPHOSPHONATE OF THE FORMULA 